The long-standing quest for aliens just got a big boost.

Scientists have discovered that phosphorus, a key building block of life, exists in the ocean beneath the icy surface of Saturn’s moon Enceladus.

The discovery was based on a review of data collected by NASA’s Cassini probe, and was published Wednesday in the leading journal Nature.

Cassini began exploring Saturn and its rings and moons in 2004, before burning up in the gas giant’s atmosphere when its mission ended in 2017.

“This is an amazing discovery for astronomy,” said Christopher Glenn of the Southwest Research Institute, one of the paper’s co-authors, adding: “We found abundant phosphorus in ice samples from the subsurface ocean. Quantity found.”

Geysers at Enceladus’ south pole spew icy particles into space through fissures in the surface, feeding Saturn’s E ring—the blur outside the bright central rings.

Scientists had previously found other minerals and organic compounds in the ice grains, but not phosphorus, which is an essential building block for DNA and RNA, and is essential for people, animals and even marine plankton. Also found in bones and teeth.

Simply put, life as we know it would not be possible without phosphorus.

While geochemical modeling had previously found it would contain phosphorus, and the prediction was published in an earlier paper, it’s one thing to predict something and another to confirm it, Glenn said. Is.

“This is the first time that this essential element has been discovered in an ocean outside of Earth,” first author Frank Postberg, a planetary scientist at Frei Universität Berlin, said in a NASA statement.

To make the new discovery, the authors combed through data collected by Cassini’s Cosmic Dust Analyzer instrument, and confirmed the results by conducting laboratory experiments to show that phosphorus in Enceladus’ ocean water. It exists within different forms of solution.

Over the past 25 years, planetary scientists have discovered that worlds with oceans beneath the ice surface are common in our solar system.

These include Jupiter’s moon Europa, Saturn’s largest moon Titan, but an even more distant body, Pluto.

Although Earth-like planets with surface oceans need to maintain the right temperature for life within a narrow window of distance from their host star, the number of discoverable habitable bodies for worlds with subsurface oceans is limited. Increases that may be present.

“With this finding, Enceladus’ ocean is now known to support what is generally thought to be the most stringent requirement for life,” Glenn said.

“The next step is clear — we have to go back to Enceladus to see if a habitable ocean really exists.”